Slotted vane turbine governor



Nov. 29, 1960 2,962,258

W. A. WAGNER SLOTTED VANE TURBINE GOVERNOR Filed March 51, 1958 SPRINGTLRBIN SPEED INVENTOR.

WILLIAM A. WAGNER I point.

storrnn VANE TURBINE GOVERNOR William A. Wagner, Sepulveda, Calif.,assignor to The Marquardt Corporation, a corporation of California FiledMar. 31, 1958, Ser. No. 724,987

8 Claims. (Cl. 25359) This invention relates to slotted vane turbinegovernors and more particularly to slotted vanes which produce a minimumaerodynamic load on the governor mechanism for controlling the vanes.

As illustrated in United States Patent No. 2,815,188, granted December3, 1957, to Dwight D. Nelson, ram air turbines have utilized vanes movedby a governor mechanism to vary the mass flow through a ram air turbineto control the speed. Since the vanes assume various angles of attackrelative to the air flow through the turbine, a variable aerodynamicload is transmitted to the governor mechanism. This aerodynamic vaneload at any given position of the vane together with the force of thefiyballs and the spring force determine the operating characteristic ofthe governor. Since the aerodynamic vane load is not constant throughoutthe control speed range but increases with increase in angle of attackof the vanes, it is difficult to obtain a governor spring which cancompensate for the variable vane load in order to provide propergovernor control.

The present invention utilizes slots in the governor vanes to spoil thelift of the vanes and thus prevent the development of highly variablevane loads on the governor. While the vane loads developed by theslotted vanes may increase slightly with increased angleof the vanes,this increase can be easily compensated for by, the selection of agovernor spring which will substantially reduce the governing band. Theslotted vanes are moved directly by the fiyballs which act against thegovernor spring and the vanes control the air flow through the ram airturbine to control the speed of the turbine. The vanes are pivotallymounted for angular movement and a slot can be placed in each vaneupstream of the pivot The size and angle of the slot and the location ofthe slot in each vane can be varied for each particular application.

It is therefore an object of the present invention to provide slottedgovernor vanes for a turbine in order to minimize the aerodynamic loadsof the governor vanes.

Another object of the invention is to provide a governor for a ram airturbine in which slotted vanes are utilized to control air flow throughthe turbine in order to regulate its speed.

These and other objects of the invention will become readily apparentfrom the accompanying description and drawings in which:

Figure 1 is a side elevational view, partly in section, showing a ramair turbine and slotted governor vanes;

Figure 2 is an end elevational view of the ram air turbine along line 22of Figure l;

Figure 3 is a horizontal section along line 3-3 of Figure 1 illustratingthe slotted governor vanes;

Figure 4 is an end elevational view of one of the' governor vanes; and

Figure 5 is a graphic illustration of the aerodynamic vane loadresulting from slotted governor vanes.

Referring to the embodiment of the invention chosen States PatentO2,962,258 Paftented Nov. 29, 1960 ice I for illustration, the ram airturbine 10 can be supported in any suitable manner for insertion intothe air in order to produce power. The turbine comprises a cup shapedstationary housing 11 having a central, hollow projection 12. A turbineshaft 13 extends through projection 12 and is supported for rotation bybearings 14 and 15 located between the projection and the shaft. Areduced end of shaft 13 extends through a rotor hub 16 to which issecured a plurality of turbine blades 17 by means of bolts 18. Also, thereduced end extends through back plate 19 of the nose section 20 andboth the nose section and hub 16 are secured to shaft 13 by the nut 21.In assembled condition, the hub 16 and cylindrical sleeve 22 serve toretain the bearings 14 and 15. It is apparent that therotation ofturbine blades 17 will cause rotation of shaft 13 and nose section 20.The end of shaft 13 opposite the rotor hub can be connected to anysuitable power developing device, such as electrical generator orhydraulic pump, which is to be operated at substantial constant speed.

The side 23 of housing 11 contains a plurality of open ings 24 each ofwhich contains a socket 25. Each socket 25 receives the ball end of ashaft 26, which extends through an opening 27 in one of the governorvanes 28 and is rigidly secured to the vane at locations 29 and 30. Theopposite ball end of each shaft 26 is located in one of a plurality ofsockets 31 located around the in groove 51. full lines in the fully openposition in which the vanes circumference of ring 32. The ring 32 issupported by a plurality of struts 33 connected with the forward end ofside 23 so as not to interfere with rotation ofthe turbine blades. 17 orangular movement of, governor vanes 28. Ring 32 and side 23 of housing11 define an annular air passage 34 through which flows ram air in thedirection indicated by the arrows of Figure l to drive the turbineblades 17.

An annular space 35 is located between projection 12 and side 23 andcontains governor spring 36. One end of the spring bears against -a shim37 located adjacent base 38 of housing 11 and the other end of thespring engages a slidable member 39. The base 38 and member 39 havegrooves 40 and 41, respectively, which receive and position the ends ofthe spring. The member 39 also has cylindrical sliding surfaces 42 and43 which engage projection 12 and side 23, respectively, and serve toguide the movement of member 39. An annular bearing 44 is located onmember 39 and supports an angular member 45 for rotation, relative tomember 39. The angular member 45 receives the force produced by aplurality of flyweights 46 which rotate with rotor hub 16. Eachflyweight is located at one end or" an L- shaped arm 47 which ispivotally connected by a pin 48 to a set of lugs 49 carried by the rotorhub 16. The other end of each arm 47 carries a roller 50 which engagesthe angular member 45 and causes member 45 to rotatewith turbine hub 16.As the flyweights 46 move outwardly under the influence of centrifugalforce, the rollers 50 move member 39 axially and compress spring 36.

The member 39contains an annular, circumferential groove 51 whichslidably receives a pin 52 for each governor vane 28 and each pinprojects through one of the openings 24 into a socket 53 in the innerend of one of the vanes. Referring to Figures 3 and 4, the inner endof-each vane 28 is reduced and carries an actuating arm 54 containingthe socket 53. As member 39 is moved rearwardly by the flyweights, thepins 52 will pivot 'the governor vanes 28 about shafts 26 in a direction to reduce the area of passage 34. At the same time, the pins 52will move in openings 24 and will slide In Figure 3, the vanes 28 areshown by are at a low angle of attack to the air flow. In the dottedline position of Figure 3, the pins 52 have been moved by the flyweightsto increase the angle of attack of the vanes and reduced the flow areaof passage 34.

Because of the location of shaft 26 in each of the vanes, the lift forceon the vanes will produce a force tending to move the vanes in adirection to close passage 34 and thus the lift force acts with theforce of the flyweights. Also, since each of the vanes is in the form ofan airfoil, the lift of the vanes would normally increase substantiallywith increase in angle of attack. Such an increase in lift force or vaneload would substantially effect the control characteristics of thegovernor since the force acting against the spring at overspeeds wouldbe the sum of flyball forces and varying vane loads. In order tominimize the variations in lift force or vane load, a slot 55 ispositioned behind the leading edge of each vane. The slots have theeffect of spoiling the lift of the vane at all angles of attack so as toreduce the vane loads. As illustrated in Figure 3, the slots 55 aresubstantially transverse of the vanes and, at all angles of attack ofthe vanes, the slots permit air flow from one surface to the othersurface of the vanes in a direction having an axial component. It isunderstood that the size and position of the slots, as well as thedirection of the slots, can be varied to obtain the best results for anyparticular ram air turbine. Also, it is not necessary that every vanecontain a slot or that the same shape of slot be utilized for everyvane.

Referring to Figure 5, the governor forces are graphically illustratedas opening and closing forces on the vanes. The force of spring 36, asillustrated by curve A, is always in a direction to open the passages 34while the vane load (curve B) and the flyweight force (curve C) arein adirection to close passage 34. As illustrated by curve D, the vane loadfor non-slotted vanes would increase rapidly and in an irregular mannerover the speed range with accompanying variation in angle of attack.However, the curve B for slotted vanes illustrates that only a smallincrease in vane load results over the speed range and that thisincrease is at a substantially uniform rate so that the vane load can beeasily compensated for in the design of the spring. The vane load curvesB and D represent the combined forces on the vanes resulting from liftdeveloped by the vane andfrom the fluid impact on the projected area ofthe vane presented to the air flow. It is understood that with some vanemounting, the vane loads could produce a vane closing force which wouldact with the spring force and against the flyball force.

In the operation of the ram air turbine, the governor will maintain asubstantially constant speed of shaft 13 since overspeeding of the shaftwill cause the flyweights to move the governor vanes in a direction toclose the air passage 34. With the slotted vanes, the governor can beconstructed for more accurate speed control. It is understood thatthepresent invention can be utilized with various blade and governorconstructions and with various turbine constructions which utilize airor any other suitable working fluid. Various other modifications arecontemplated by those skilled in the art without departing from thespirit and scope of the invention as hereinafter defined by the appendedclaims.

What is claimed is:

1. In a ram air turbine having turbine blades located in an annularfluid passage, flyball means responsive to the speed of said turbine,means movable by said flyball means in response to a change in speed ofsaid turbine, spring means operable upon said movable means for opposingmovement of said movable means by said flyball means, a plurality ofvanes in said passage having an airfoil shape, means for pivotallymounting said vanes, means connecting said vanes with said movablemember for-pivotally moving said vanes to control the air flow throughsaid passage and the speed of said turbine, and a slot in at least someof said vanes to spoil the lift thereof in order to minimize theaerodynamic vane load transmitted to said movable means.

2. In a ram air turbine as defined in claim 1 wherein said pivotalmounting means for each of said vanes comprises a shaft positionedradially in said passage, each of said vanes being located in a radialposition in said passage and extending axially of said passage, thepivotal movement of said vanes causing a change in the angle of saidvanes presented to the fluid flow through said passage.

3. In a turbine having blades located in a fluid passage and its speedcontrolled by a flyball mechanism operable against a governor spring, aplurality of airfoil vanes located in said passage and movable by saidflyball mechanism to control the fluid flow through said passage and thespeed of said turbine by varying the area of said passage, and a slotlocated in at least some of said vanes to spoil the lift thereof andcause the aerodynamic vane load transmitted to said flyball mechanismand spring combination to increase at a low, uniform rate duringmovement of said vanes to reduce the area of said passage.

4. In a turbine as defined in claim 3 wherein said vanes are locatedradially in said passage and extend lengthwise of the passage, means forpivotally mounting each of said vanes about an axis extending radiallyof said passage, said flyball mechanism causing pivotal movement of saidvanes about said axis.

5. In a turbine as defined in claim 4 wherein said slots are positionedin said vanes at a location betvken said pivotal axis and the leadingedge of the vanes.

6. In a turbine having blades located in a fluid passage, governor meansconnected with said blades and responsive to the speed of rotation ofsaid blades, a plurality of airfoil vanes located in said passage andmovable by said governor means to control the fluid flow through saidpassage and the speed of said turbine by varying the area of saidpassage, and an opening located in at least some of said vanes to spoilthe lift thereof in order to minimize the aerodynamic vane loadtransmitted to said governor means during movement of said vanes toreduce the area of said passage.

7. In a turbine having radial blades located in an annular fluidpassage, governor means connected with said blades and responsive to thespeed of rotation of said blades, aplurality of airfoil vanes radiallypositioned in said passage and pivotally movable by said governor meansto control the fluid flow through said passage and the speed of saidturbine by varying the area of said passage, ,a slot in at least some ofsaid vanes to spoil the lift thereof and cause the aerodynamic vane loadtransmitted to said governor mechanism to increase at a low, uniformrate during angular movement of said vanes to .reduce the area of saidpassage.

8. In a turbine as defined in claim 7 having a radially positionedpivotal axis for each vane located intermediate the leading and trailingedge of each vane, said slots being positioned in said vanes at alocation between said pivotal axis and the leading edge.

References Cited in the file of this patent UNITED STATES PATENTS1,808,464 Huiskamp June 2, 1931 2,045,383 Faber June 23, 1936 2,073,318Peel Mar. 9, 1937 2,135,887 Fairey Nov. 8, 1938 2,340,417 Ellett Feb. 1,1944 2,749,025 Stalker June 5, 1956 2,815,188 Nelson Dec. 3, 1957FOREIGN PATENTS 7545056 Great Britain Aug. 1, 1956 764,686 Germany Mar.30, 1-953 1,081,514 France June -9, 1954

